Chapter 6. Design of Manufacturing Systems II Pull System

Transcription

1 Chapter 6 Design of Manufacturing Systems II Pull System

2 Evolution of cost, quality and worker s satisfaction: 1. Handicraft, 2.Taylorism, 3. High volume automation, 4. Flexible automation, 5. Concurrent engineering (From Sohlenius, 2005) 1 KEY Cost = Handicraft 2 = Taylorism 3 = High Volume Automation 4 = Flexible Automation 5 = Concurrent Engineering Worker's satisfaction Quality customer's satisfaction Figure by MIT OCW. After Sohlenius, 2005.

3 Driving Forces for Manufacturing Systems (From Sohlenius 2005) The 50's The 60's The 70's The 80's The 90's Efficiency of manual labor Efficiency of machine-tool utilization Minimize capital cost for products in process Order control customer adapt Quality & productivity holistically Customer, concurrent design, lean production, environment Figure by MIT OCW.

4 Numerical Control Machine Tool in 1951 J. T. Parsons, (Traverse City, Michigan) Small machine shop with milling machine and dial gages U.S. Air Force funding of the Servo-mechanisms Lab (Gordon Brown, Jay Forrester, etc.) Controversy on credit for NC machine tool development Parsons received a National Technology Medal from President Ronald Reagan

5 Manufacturing Systems Concept proposed in 1960 s by M. Eugene Merchant (1970) NEEDS (product requirements) CREATIVITY (product concepts) COST AND CAPABILITIES PRODUCT DESIGN PRODUCTION PLANNING PRODUCTION CONTROL PRODUCTION EQUIPMENT PRODUCTION PROCESSES FINISHED PRODUCTS for production programming feedback, supervisory, adaptive optimizing including machine tools removal, forming, consolidative fully assembled, inspected & ready for use PERFORMANCE Figure by MIT OCW.

6 CIRP Definition of Manufacturing System The manufacturing system is defined as An organization in the manufacturing industry for the creation of production. In the mechanical and electrical engineering industries a manufacturing system in general has an integrated groups of functions: They are the sales, design, manufacturing production, and shipping functions. A research function may provide a service to one or more of the other functions.

7 Introduction to Manufacturing System What are typical manufacturing systems? Typically, manufacturing systems are classified in terms of the physical machine arrangement. Production job shop Transfer lines Flow lines group technology Lean, linked cell manufacturing systems

8 Introduction to Manufacturing System The cost of most manufacturing systems varies depending on Production volume Degree of automation Labor cost Equipment costs Location.

9 for a Pull System Step 1. Choose FRs in the Functional Domain FR1 = Maximize the return on investment (ROI) ROI= Sales Cost Investment

10 Step. 2. Mapping of FRs in the Physical Domain to Determine DPs DP1 a = Manufacturing system to provide products at a minimum cost or DP1 b = Manufacturing system design to provide products customers demand

11 Step 3. Decompose FR1 in the Functional Domain Zigzagging between the domains FR11 = Increase the sales revenue FR12 = Minimize the manufacturing cost FR13 = Minimize manufacturing investment ROI = Sales Cost Investment

12 Step 4. Find the Corresponding DP1x's by Mapping FR1x's in the Physical Domain Decomposition of DP1 a DP1 a 1 = Maximization of production output DP1 a 2 = Unit cost minimization DP1 a 3 = Machine utilization Decomposition of DP1 b DP1 b 1 = Product design and manufacture to maximize customer satisfaction DP1 b 2 = Target production cost DP1 b 3 = Investment in production with a systems thinking approach

13 Step 5. Determine the Design Matrix The second design represented by DP1 a x's satisfies FR1x. Similarly, the second design represented by DP1 b x's satisfies FR1x. FR11 FR13 = FR DP1 a 1 XX 0 DP1 a 3 XXX DP1 a 2 (2) FR11 FR12 FR13 X00 DP1 b 1 = XX0 DP1 b 2 XXX DP1 b 3 (4)

14 Step 6. Zigzag Decompose FR11, FR12 and FR13 by going from the Physical to the Functional Domain and determine the corresponding DPs (Level 3) Step 6-a. Decompose FR11 (Increase the sales revenue) and DP11 (Product design and manufacture to maximize customer satisfaction) and determine DPs FR111 = Sell products at the highest acceptable price FR112 = Increase market share (volume) DP111 = Customer perceived value of product improved DP112 = Broad product applications FR111 FR112 = X0 DP111 XX DP112 (6)

15 Step 6. Zigzag Step 6-a. Decompose FR11 (Increase the sales revenue) and DP11 (Product design and manufacture to maximize customer satisfaction) and determine DPs FR111 = Sell products at the highest acceptable price FR112 = Increase market share (volume) n SR = (Pr ice i Volume ) i i = 1 DP111 = Customer perceived value of product improved DP112 = Broad product applications FR111 FR112 = X0 DP111 XX DP112 (6)

16 Step 6-b. Decompose FR12 (Minimize the manufacturing cost) and Determine DPs FR12 (Minimize the production cost) may be decomposed with DP12 (Target production cost) in mind as FR121 = Reduce material costs FR122 = Reduce operational activity costs FR123 = Reduce overhead The corresponding DPs may be stated as: DP121 = Target price given to suppliers DP122 = Targeted performance of operational activities DP123 = Right size business processes The elements of the production cost are the cost of raw materials and components, the direct cost, indirect cost, and administrative costs or overhead.

17 Step 6-b. Decompose FR12 (Minimize the manufacturing cost) and Determine DPs FR12 (Minimize the production cost) may be decomposed with DP12 (Target production cost) in mind as FR121 = Reduce material costs FR122 = Reduce operational activity costs FR123 = Reduce overhead The corresponding DPs may be stated as: Design Matrix DP121 = Target price given to suppliers DP122 = Targeted performance of operational activities DP123 = Right size business processes FR121 FR122 FR123 X00 DP121 = 0X 0 DP122 00X DP123

18 Step 6-c. Decompose FR13 (Minimize manufacturing investment) and select DPs FR13 (Minimize production investment) may be decomposed with DP13 (Investment in production with a system thinking approach) in mind as FR131 = Acquire machines with cycle time the minimum takt time FR132 = Ensure flexibility to accommodate capacity increments at lowest cost FR133 = Develop flexible tooling FR134 = Ensure flexibility to accommodate future products

19 FR131 = Acquire machines with cycle time (less than or equal to) the minimum takt time FR132 = Ensure flexibility to accommodate capacity increments at lowest cost FR133 = Develop flexible tooling FR134 = Ensure flexibility to accommodate future products The corresponding DPs may be stated as: DP131 = Machine design focused on customer demand pace and value added work DP132 = Linked cell manufacturing systems DP133 = Flexible tooling design DP134 = Movable machines and reconfigurable stations to enable new cell design

20 Step 6-c. Decompose FR13 (Minimize manufacturing investment) and select DPs FR13 (Minimize production investment) may be decomposed with DP13 (Investment in production with a system thinking approach) in mind as Design Matrix FR131 FR132 FR133 FR134 = X 000 DP 131 XX 00 DP X 0 DP X DP 134

21 Step 7. Fourth Level Decomposition Step 7-a. FR11 Sales Revenue Branch Functional requirement FR111 (Sell products at the highest acceptable price) must be decomposed with DP111 (Customer perceived value of product improved). FR111 may be decomposed as follows: FR1111 = Increase the appeal of products by providing desired functions and features FR1112 = Increase the reliability of products FR1113 = On time delivery (for a variety of products) FR1114 = Decrease variation of the delivery time FR1115 = Provide effective after sales service

22 Step 7. Fourth Level Decomposition The corresponding DPs are: Step 7-a. FR11 Sales Revenue Branch DP1111 = Design of high quality products that meet customer needs as specified by FRs and Cs DP1112 = Robust design of products DP1113 = Production based on actual demand DP1114 = Predictable production output DP1115 = Service network The design equation and matrices are as follows: FR 1111 FR 1112 FR 1113 FR 1114 FR 1115 = X 0000 XX XX 00 0 XXX 0 0 X 00 X DP 1111 DP 1112 DP 1113 DP 1114 DP 1115

23 Step 7. Fourth Level Decomposition FR112 (Increase market share (volume)) must be decomposed with DP112 (Broad product applications). FR111 may be decomposed as follows: FR1121 = Development of niche (new or custom) products FR1122 = Development of multiple solutions within the product line The corresponding DPs are: DP1121 = Short product development process DP1122 = Product variety The design equation and matrices are as follows: FR1121 FR1122 = X0 DP1121 XX DP1122 (10)

24 Step 7-b. FR12 Production Cost Branch FR 122 (Reduce operational activity costs) and DP122 (Target production cost) may be decomposed as FR1221 = Reduce transport costs FR1222 = Reduce setup costs FR1223 = Reduce costs of manual operations (mach. load/unload, assembly, inspect.) FR1224 = Reduce fabrication costs FR1225 = Reduce maintenance costs The corresponding DPs are: DP1221 = Product-flow oriented layout DP1222 = Setup performed with reduced resources DP1223 = Effective use of the workforce DP1224 = Fabrication parameters based on takt time to increase tool life DP1225 = Total productive maintenance program The design is an uncoupled design.

25 Step 8-a. FR11 Sales Revenue Branch Axiomatic Design Steps Step 8. Fifth Level Decomposition FR 1112 (Increase the reliability of products) and DP1112 (Robust design of products) may be decomposed as FR11121 = Determine the lowest tolerable stiffness of the product FR11122 = Determine the design range for manufacturing tolerance FR11123 = Select manufacturing operations with a system range that is within the design range The corresponding DPs are: DP11121 = Mathematical model for stiffness determination DP11122 = Mathematical model for derivation of design range for PVs DP11123 = Selected machines with appropriate system range for PVs The design equation and matrices are as follows: FR11121 X00 DP11121 FR11122 = XX0 DP11122 FR11123 XXX DP11123 (12) The design matrix is triangular and thus, it is a decoupled design.

26 Step 8-a. FR11 Sales Revenue Branch Axiomatic Design Steps Step 8. Fifth Level Decomposition Functional requirement FR1113 (Decrease mean delivery time) must be decomposed with DP1113 (Production based on actual demand). FR1113 may be decomposed as follows: FR11131 = Produce at the customer demand cycle time (or takt time) FR11132 = Produce the mix of each part type demanded per time interval FR11133 = Be responsive to the downstream customer s demand time interval The corresponding DPs are: DP11131 = Linked-cell manufacturing system balanced to customer demand DP11132 = Level production DP11133 = Reduced response time across the production system The design matrix FR11131 FR11132 FR11133 X00 DP11131 = 0X 0 DP11132 XXX DP11133

27 A Linked-cell Manufacturing System to Illustrate the Concept. The machines are arranged in a cellular structure. In this figure, two workers are moving in two loops opposite to the flow of the work piece (Cochran, 1998). Straighten Crack detect Induction temper Resistance harden teeth Buff OD rack 7 2 Wash Super finish OD Assemble pistons Broach teeth Lap journal 9 Centerless grinder OUT Final wash (rust prevent) Straighten Scan harden journal IN 1 Deburr 11 Turn piston groves Drill cross holes Broach end slots Machine both ends Figure by MIT OCW.

28 Step 8-a. FR11 Sales Revenue Branch Axiomatic Design Steps Step 8. Fifth Level Decomposition Functional requirement FR1114 (Decrease variation of the delivery time) and DP1114 (Predictable production output) must be decomposed. FR1114 may be decomposed as follows: FR11141 = Respond quickly to production problems FR11142 = Produce with a predictable quality output FR11143 = Produce with a predictable time output The corresponding DPs are: DP11141 = Visual control system to provide rapid response DP11142 = Production with no defects and the ability to identify root cause DP11143 = Predictable production resources The design equation and matrices are as follows: FR11141 X00 DP11141 FR11142 = XX0 DP11142 FR11143 XXX DP11143 (14)

29 Step 8. Fifth Level Decomposition Step 8-b. FR12 Manufacturing Cost Branch FR 1223 (Reduce costs of manual operations (mach. load/unload, assembly, inspect.)) may be decomposed with DP122 (Effective use of the workforce) in mind as FR12231 = Reduce tasks that tie the operator to the machine FR12232 = Enable worker to operate more than one machine or station FR12233 = Plan the resources to produce with different production volumes The corresponding DPs are: DP12231 = Machines & stations designed to run autonomously DP12232 = Work-loops implemented in a cell layout DP12233 = Standardized work-loops designed for different volumes The design equation and matrices are as follows: FR12231 X00 DP12231 FR12232 = XX0 DP12232 FR12233 XXX DP12233 (15)

30 Step 9. Sixth Level Decomposition: FR11 Sales Revenue Branch Functional requirement FR11131 (Produce at the customer demand cycle time (or takt time) and DP11131 (Linked-cell manufacturing system balanced to customer demand) may be decomposed as follows: FR = Define customers, parts, and volumes for each sub-system or cell within production FR = Design sub-system for a range of volume fluctuation DP = Configuration of sub-systems to enable flow at the ideal range of cycle times DP = Cell or sub-system designed to meet the minimum takt time The design equation and matrices are as follows: FR FR = X 0 XX DP DP (16)

31 FR11132 (produce the mix of each part type demanded per time interval) and DP11132 (Level production) may be decomposed as follows: FR = Produce in small run sizes FR = Convey in small and consistent quantities FR = Produce and supply only the parts needed The corresponding DPs are: DP = Short setup time DP = Standard containers that hold small amounts of parts DP = Information system to produce only the parts needed (Pull system) The design equation and matrices are as follows: FR X00 DP FR = XX 0 DP FR XXX DP This design is a decoupled design and thus, satisfies the Independence Axiom. (17)

32 FR11133 (be responsive to the downstream customer s demand time interval) must be decomposed with DP11133 (reduced response time across the production system) in mind. FR11133 may be decomposed as FR = Reduce sub-system replenishment time to less than the customer demand interval. FR = Ensure that sufficient parts are available to satisfy the customer demand interval. The corresponding DPs are DP = Elimination of wastes that cause excess lead-time DP = Standard work-in-process (swip) quantity of parts The design equation and matrices are as follows: FR FR = X 0 X X DP DP (18) This design is a decoupled design and thus, satisfies the Independence Axiom.

33 FR11142 (produce with a predictable quality of output) must be decomposed with DP11142 (production with no defects and with the ability to identify root cause) in mind. FR = Ensure capable processes. FR = Decrease sources of variation due to multiple flow paths. FR = Prevent making defects throughout. FR = Do not advance defects to the next operation. The corresponding DPs are: DP = Capable machines, equipment, tools, and fixtures DP = Single path through manufacturing system and external supplier (no parallel processing) DP = Use of standards and devices to prevent defects DP = Use of successive checks to detect defects if they do occur The design equation and matrices are as follows: FR FR FR FR = X X X 0 0 X 0 X X DP DP DP DP (19)

34 Step 10. Seventh-Level Decomposition: FR11 Sales Revenue Branch FR (design sub-system for a range of volume fluctuations) must be decomposed with DP (sub-system designed to meet the minimum TAKT time) in mind. FR = Select appropriate manufacturing process. FR = Design manufacturing process cycle time at each station to meet minimum TAKT time. FR = Design station fixtures to enable minimum TAKT time. The corresponding DPs are: DP = Physics of the manufacturing process DP = Manufacturing process work content defined to be less than the minimum TAKT time DP = Fixture design to provide quick load/unload (within required tolerance) The design equation and matrices are FR FR FR = X 0 0 X X 0 X X X DP DP DP (20)

35 Flow Chart of the Manufacturing System Design M1 M11 M111 M1111 M112 M1121 M1122 M1112 M11121 M11122 M11123 M1113 M11131 M M M11133 M M M M M M11132 M M M M1114 M11141 M11142 M11143 M M < M M1115 M12 M121 M13 M131 M132 M122 M1221 M1222 M133 M134 M1223 M12231 M12232 M12233 M1224 Summation Junction M1225 Control Junction M123

36 Use of the Flow Chart of the Manufacturing System Design 1. Diagnosis 2. Engineering changes 3. Job assignment and management 4. Distributed systems 5. Software development